Browntail Moth and Schools

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Maine Forest Service

Browntail Moth and Schools

Schools are critical spaces to recognize and respond to browntail moth (BTM) infestations to avoid impacts to students and staff. While long-lasting tree defoliation and branch dieback are concerns, impacts to the health of students and staff are the most pressing concerns around schools. The microscopic, toxic hairs of BTM can cause trouble breathing and skin irritation similar to poison ivy lasting from a few hours up to several weeks. Some people say they experience itching with fewer than ten webs per tree or shrub; others say they have no symptoms from heavier infestations around their yards. In 2021, Maine Forest Service (MFS) surveys uncovered populations of this insect in every Maine county except York, where it is also likely to be found.

In areas where BTM is not managed, exposures to the toxic hairs peak from late-May through July but are possible throughout the year. You can take actions right now, from February to the end of March, to reduce impacts at the end of the school year along with any summer use of the school grounds. There is only a short window of time to complete these actions. Please consider speaking with your facilities manager, custodians, and staff now to create an action plan. Follow the Four Rs (Recognize, Remove, Recruit, and Reach Out) below to create this plan.

Specific Requirements for School Properties

Reminder: Taking action and keeping records of pest prevention and management activities on school properties is the responsibility of your school Integrated Pest Management (IPM) Coordinator. Be sure to report and coordinate all pest sightings and pest management activities, including browntail moth winter web sightings and removal, with your IPM Coordinator. Record-keeping forms and other resources can be found at, and Hillary Peterson, the IPM Entomologist with the Department of Agriculture, Conservation and Forestry can be reached at


Learn how to tell if the trees around your school have BTM. The winter webs of BTM can look like single leaves hanging onto twigs or fist-sized clumps of leaves tied together tightly with silk. Additional resources to support recognition are found on our websiteDo this as soon as possible.

Two photos showing winter webs

Webs can look like fist-sized clumps of leaves tied together tightly with silk, or like single leaves hanging onto twigs.


Use hand snips, loppers or extendable pole prunersto remove webs within reach from the ground and away from hazards such as powerlines. Protect your eyes and skin from hairs that might be present from past caterpillar activity. After removal, destroy webs by burning or soaking in soapy water for several days, then dispose of the soaked webs in the trash. Do this before April!

Man using pruners on tree

Use hand snips or extendable pole pruners to remove webs within reach from the ground and away from hazards such as powerlines.


Hire professional help to treat webs out of reach or near hazards. Line up help during winter. Licensed Professional Arborists can remove BTM webs in larger trees and shrubs in the winter. In trees where the caterpillars' hairs cause a nuisance and where it is not practical to remove the webs, Licensed Pesticide Applicators may be able to use insecticides during the growing season to manage BTM. Do this as soon as you know you will need the help.

Browntail moth winter webs in large oak trees

In large, heavily infested trees like these oaks removal of webs may not be practical because of time and cost involved in this approach. In trees like this that are a concern from the standpoint of human health or nuisance, licensed pesticide applicators may be able to use insecticides to help reduce impacts from browntail moth.

If there are places near the school where you cannot manage populations, plan for how the school community will respond to their presence. Depending on the size of the population and locations, steps you might consider include: 

  • Excluding activity near infested trees 
  • Changing maintenance schedules (such as mowing) 
  • Rerouting student access to schools. 

Plans will vary depending on your situation and may need to be evaluated on an ongoing basis. 

Reach Out

We encourage you to reach out to your communities to provide information on this caterpillar, help them save their skins and their summers! Also, please reach out to us if you need additional advice. information on biology and management of browntail moth information on integrated pest management on school grounds



February 10, 2022, 4 PM

Blue Hill Heritage Trust, Island Heritage Trust, Hancock County Soil and Water Conservation District, Great Pond Mountain Conservation Trust, and Frenchman Bay Conservancy are hosting a conversation bout BTM in the region with State Entomologist and Director of MFS Forest Health and Monitoring Allison Kanoti. A brief overview of the problem and management approaches will be presented. Register for this webinar

February 16, 2022, 9:15 to 10:15 AM
University of Massachusetts' Cooperative Extension program is hosting MFS Forest Entomologist Tom Schmeelk to talk about BTM and What You Should Know.  Details may be found on the Extension's events web page.

February 17, 2022, 7 PM
The Lewiston Auburn Community Forestry Board and Auburn Conservation Commission are teaming up to host an evening discussion on BTM and other invasive pests with Director of MFS Forest Health and Monitoring Allison Kanoti. Attend meeting on Zoom. A complementary field session has been set up for February 19, 2022, 10:00 to 11:30 AM, hosted by Auburn City Arborist  

LACFB will be coordinating a field session in March, details to be determined. 

March 5, 2022
Maine Arborist Association is planning a return to their annual in-person meeting March 5 in Portland, ME. Maine Forest Service will provide updates on topics including BTM, forest health and Project Canopy. Visit the MAA website for updates and registration details.

Knock Out Browntail

For more information:

Contact 211 Maine for answers to BTM FAQs:

  • Call 211 or 1-877-463-6207
  • Text your ZIP code to 898-211

Or visit the MFS website. While you are there, sign up for the BTM News Bulletin.